If I made his legs longer that may make him taller instead of streching the torso, hands are average ,it may be that theyre lighter in color and closer and appear larger, still a good observation and thanks for sharing your view :)

For most humans, the hand extends from the bottom of one's chin to just above one's eyebrows (the middle finger will rest there if the bottom of the palm is placed level at the bottom of the chin). I measured the hands in this pic, and compared them to the size of the head: they are a little large, but that doesn't bother me much, as I'm pretty sure that they're larger on the engineers in the film. Bigger hands=more power.

I'd leave them be, but if you want to switch them, then go on ahead - I won't stop you.